Strain insulator



Feb. 19,1924. 1,484,447

H. B. GEAR STRAIN INSULATOR Filed April 1917 2 SheeSSheet 1 Feb'. 19 1924. 1,484,447

H. B. GEAR STRAIN INSULATOR Filed April 9. 1917 2 SheetsSheet 2 Q; Ill

Patented Feb. 19, 1924.

UNITED STATES PATENT oFncE.

HARRY B. GEAR/,0! CHICAGO, ILLINOIS, ASSIGNOR TO Gr. & W. ELECTRIC SPECIALTY C0,, OF CHICAGO, ILLINOIS, A CORPORATION OF ILLINOIS.

STRAIN INSULATOR.

Application filed April 9,

To all whom it may concern:

Be it known that I, HARRY B. GEAR, a citizen of the United States, residing at Chicago, in the county of Cook and State of Illinois, have invented a certain new and useful Improvement in Strain Insulators, of which the following is a full, clear, conelse, and exact description, reference being had to the accompanying drawings, forming I0 a art of this specification.

y invention relates to strain insulators; that is, to insulators for supporting electric wires, conductors and so on, which are under strain or tension.

The principal object of the invention is to provide a simple, practical and effective device of this kind.

Other objects of the invention are to reduce the cost of manufacture, to simplify the construction, to arrange for the easy and ready manipulation of the device and the attachment and detachment of the conductors or wires thereto, to insure efiiciency and effectiveness of operation, to permit the sealing of the conductors inthe device if desired, and to secure other advantageous results as will appear hereinafter.

In the accompanying drawings Fig. 1 is a longitudinal section of a strain insulator 80 embodying my present invention, together with a portion of a building to which the same is attached and end portions of conductors supported by the insulator;

Fig. 2 is a cross section taken on line 2-2 in Fig. 1;

Fig. 3 is an end view of the insulator; Fig. 4 is a view of a detail of construction; Fig. 5 is a longitudinal section of a modified form of device;

Figs. 6, 7 and 8 are views of details of construction of said modified form;

Fig. 9 is a longitudinal section of a further modification; and 1 Figs. 10 and 11 are longitudinal sections 46 of still further modifications.

Referring first to the device shown in Figs. 1 to 4 inclusive, 1 illustrates a portion of a wall of a building or other member or element to which the device is to be connected. This wall 1 is shown provided with an eyelet 2 to which the strain insulator may be attached. The insulator itself comprises an outer member 3 and an inner member 4, which latter is provided with a hook 5 1917. Serial No. 160,669.

adapted to engage the eyelet 2 on the wall 1. The outer member 3 is provided with a conical interior, as well shown in Fig. 1, and the exterior of the member 4 is generally conical so as to fit within the member 3, said member 4 being shown in side elevation in Fig. 4. Said members 3 and 4 are capable of relative adjustment with reference to one another, in fact the member 4 may be bodily removed from the member 3, the member 3 however having a transverse wall portion 5 substantially closing its smaller or inner end, against which portion the member 4 may abut. This wall portion 5 is provided with one or more apertures, preferably four, as shown in Fig. 3. These consist of an upper or isolated aperture 6, and three lower apertures 7, 8 and 9, arranged adjacent to one another, the middle one 8 being preferably diametrically opposite the aperture 6. These apertures 6, 7, 8 and 9 are for conductors to be connected or supported by the strain insulator, two of such conductors 10 and 11 being shown in Fig. 1. In this case these two conductors pass preferably through the opposite apertures 6 and 8. In case there are three conductors they would preferably pass through the apertures 6, 7, and 9, the aperture 8 not containing a conductor. In this way the two or three conductors, as the case may be, may be accommodated in an efficient manner, without subjecting the device to an undesirable twisting or torsional strain. The member 4 is preferably provided with longitudinally extending grooves or channels which are shown more in detail in F igs. 5 and 7. An upper relatively large groove or channel 12 is shown in position to be in alinement with the aperture 6 of the member 3, when the member 4 is inside of the member 3. Thus a single conductor passing through the aperture 6 may also lie in the channel or groove 19.. On opposite sides of the channel 152 are relatively small chan nels 13 and, 14 which are to accommodate conductors of smaller size, in which case either one or the other of the channels 13 or 14 may be brought into alinement with the apertures 6. Opposite the channel 12 1s another relatively large channel 15 which can accommodate another conductor passing through the aperture 8, thus taking care of two large conductors passing through the apertures 6 and 8. Other relatively large tion within the member grooves or channels 16 and 17' are on opposite sides of the channel 15, the channels 16 and 17 coinciding in position with the ag icrtures 7 and 9 when the member at is in such position that 12 registers with 6 and 17 with Relatively small channels 18 and 19 are preferably located on one side of the channels 16 and 17, respectively, whereby relatively small conductors may be taken care of in the same way that relatively large ones may be. As an arrangement for holding the memher 4: in proper position within the member 3, the hook 5 is preferably provided with a shank 20 which extends through the member it and also through the end 5 of the member 3 and is threaded at its end so that it may engage a nut 21v and permit said shank to be held in position. Said shank 20 is provided with a flattened portion 22 which forms a shoulder 23 adapted to en gage a corresponding shoulder formed on the member 4, whereby the rotation of the nut 21 will cause the shoulder 23 to draw the member t closely or tightly into posi- Thus the device may be taken apart or adjusted to permit the insert-ion or withdrawal of conductors as desired, and may be tightened up so as to cause the proper engagement of the conductors between the members 3 and a, clamping them tightly to prevent slippage as may be desired. To this end the interior of the member 3 may be provided with cross corrugations or channels 24 (Fig. 1).

Referring to the modification shown in Figs. 5 to 8, inclusive, this device does not have the cross wall 5 of the device of Fig. 1, but the member 3 is open at both ends. The shank 20 of a hook similar to the hook shown in Fig. l, is extended through the inner member F and has its end provided with a flattened portion 26 (Fig. 8) which is adapted to engage a corresponding slot. 27 (Fig. 7). In this way the shank 20 engages the large end of the inner member instead of the smaller end as in Fig. 1, so that pulling upon said shank or hook tends to draw the inner member into the outer member instead of vice versa, as in the ar rangeinent of Fig. 1. The member at has a slot 28 (Fig. 6) extending completely through it capable of accommodating the enlarged end 26, the slot 27 being simply a small cross slot or recess at the large end of said member, whereby the shank 20 may be passed through the member at. from the small end to the large end thereof, and may then be given a quarter turn so as to cause the enlargement 26 to enter the cross slot 27 and thereby engage the member P, when said shank 20 is moved a short distance backwardly or toward the inner end of the member 4;. This member t is preferably provided with longitudinally extendinQ grooves 12, 13, etc., similar to those with 1 ,asaaer which the member 1 is provided as previously explained. Likewise. the member is preferably provided with annular rctzts or grooves 2} to form shoulders for engaging the conductors.

In the modification shown in Fig. 9, there is a member 3* having an interior bore or recess with a double cone or hourglass shape. and within this member 3 there are two conical members l and at with a bolt 30 extending through the same. One end of the bolt 30 is provided with a head 31. and the other end is screw threaded at 32 and a detachable thumb nut 33 is fitted on the threaded end 32. In this way the two members 4 and l can be engaged and drawn toward one another so as to clamp the conductors to any desired extent, thus affording a double clamping arrangement and also a means for holding the clamping members in position. The interior or bore of the member 23" is preferably provided with a fluted surface M.

In the modification of Fig. 10 I show a device having a single interior member 4- with the same securing bolt arrangement as shown in Fig. 9. This securing bolt 30 has its head 31 in engagement with a cross wall 5* on the outer member 3, the threaded end 32 of said bolt 30 engaging a thumb nut 33 to hold said member 4 in position. The member 4 is preferably provided with an externally fluted surface having annular iiutes or recesses 35 corresponding with similar recesses or flutes 36 in the interior or bore of the outer member 3.

In Fig. 11 I have shown a modification somewhat similar to that of Fig. 10 with the addition of a chamber 38 inside of the outer member a which chamber 38 contains insulation compound 39 such as minerallac or the like. by which the conductors 10 and 11 may be scaled. Thus not only is the device adapted for a strain insulator butv also is capable of sealing the conductors to prevent trouble and annoyance from moisture, rain. snow, sleet and the like.

The inner and outer members 4, 4*, 3, 3*, etc, are preferably made of insulating material, such as porcelain.

From the foregoing it. will be seen that the conductor or conductors are arranged within the insulator in a direction substantially lengthwise of the. direction in which they are extended and are gripped along a substantial port-ion of their length by gripping surfaces of substantial length whereby the conductors are not only engaged so as to support or suspend them in the air. but at the same time their strain is taken up and this without subjecting the conductors to a lateral or crosswise pulling moment. At the same time the pull or tension upon the insulator itself is in a longi tudinal or axial direction and consequently transverse or crosswise strains need not be provided for.

It will be understood that changes and modifications may be made without departin from the spirit of the invention.

hat I claim is:

1. A device of the class specified comprising in combination, an outer insulating member having a cone shaped chamber, an inner member having a cone shaped portion adapted to fit Within said chamber, said inner member being provided with four longitudinally extending grooves, three of which grooves are at the apices of an equilateral triangle, while the fourth is diametrically opposite one of the others, and means for connecting said members.

2. A strain insulator comprising in combination, a substantially frusto-conical inner body provided with a plurality of longitudinal grooves of various sizes in the eripheral face thereof, an outer body having a recess therein conforming substantially to the shape of said inner member for receiving the latter for longitudinal and rotative adjustment therein, said recess having disposed from end to end thereof a plurality of circumferential ribs, an integral end wall having a plurality of apertures adapted to be brought into alinement with some of the grooves in said inner body, and

means for axlally connecting said bodies.

3. A strain insulator comprising in com bination, a substantially frusto-conical inner body provided with a plurality of longitudinal grooves of various sizes in the peripheral face threeof, an outer body having a recess therein conforming substantially to the shape of said inner member for receiving the latter for longitudinal and rotative adjustment therein, said recess having disposed from end to end thereof a plurality of circumferential ribs, an integral end Wall having a plurality of apertures adapted to be brought into alinement with some of the grooves in said inner body, and a removable axial member passing through said end Wall and inner body for axially and longitudinally adjustably connecting said bodies.

In witness whereof, I hereunto subscribe my7name this 6th day of February, A. D., 191

HARRY B. GEAR.

Witnesses:

A. L. JONES, O. M. WONNIOH. 

